Inertial gas-liquid separators remove and coalesce liquid particles from a gas-liquid stream, in a crankcase ventilation application, it is desired to vent combustion blow-by gases from a crankcase of an engine. Untreated, these gases contain particulate matter in the form of oil mist and soot. It is desirable to control the concentration of the contaminants, especially if the blow-by gases are to be recirculated back into the engine's air intake system. The oil mist droplets are generally less than 5 microns in diameter, and hence are difficult to remove using conventional fibrous filter media while at the same time maintaining low flow resistance as the media collects and becomes saturated with oil and contaminants.
A gas-liquid separator in a crankcase ventilation application can be used as an air-oil separator. An air-oil separator includes a housing having an inlet for receiving an air-oil stream from an engine crankcase, and an outlet for discharging an air stream to, for example, an air intake manifold. A nozzle structure in the housing has a plurality of nozzles (holes) receiving the air-oil stream from the inlet and accelerating the air-oil stream through the nozzles. An inertial impactor in the housing is in the path of the accelerated air-oil stream and causes a sharp directional change of the air-oil stream. The sharp directional change causes oil particles to separate from the air.
U.S. Pat. No. 6,290,738 discloses an inertial gas-liquid separator including a housing having an inlet for receiving a gas-liquid stream, and an outlet for discharging a gas stream. A nozzle structure in the housing has a plurality of nozzles receiving the gas-liquid stream from the inlet and accelerating the gas-liquid stream through the nozzles. An inertial collector in the housing in the path of the accelerated gas-liquid stream causes a sharp directional change thereof and in preferred form has a rough porous collection surface (collection media) causing liquid particle separation from the gas-liquid stream of smaller size liquid particles than a smooth non-porous impactor impingement surface and without the sharp cut-off size of the latter, to improve overall separation efficiency including for smaller liquid particles. Various housing configurations and geometries are provided.
U.S. Pat. No. 7,699,029 discloses a crankcase ventilation system for an internal combustion engine having a jet pump suctioning scavenged separated oil from the oil outlet of an air/oil separator and pumping same to the crankcase. The jet pump supplies pumping pressure greater than the pressure differential between the higher pressure crankcase and the lower pressure oil outlet, to overcome such pressure differential and the back flow tendency otherwise caused thereby, and instead cause suctioning of scavenged separated oil from the oil outlet and pumping same to the crankcase.
U.S. Pat. No. 7,870,850 discloses a crankcase ventilation system for an internal combustion engine having a jet pump suctioning scavenged separated oil from the oil outlet of an air/oil separator and pumping same to the crankcase.
U.S. Pat. No. 8,202,339 discloses an inertial gas-liquid impactor separator including an inertial impactor collector having an impactor surface extending diagonally relative to axially accelerated flow, which surface is preferably a cone having a leading tip axially facing and axially aligned with the acceleration nozzle. In a further aspect, first and second inertial impactor collectors are provided in series, with an orifice in the first inertial impactor collector providing a nozzle for the second inertial impactor collector. Improved performance is provided by reducing the extent of the stagnation region to change from a narrow band particle size range to a wider band range and to shift cut-off size. An inertial gas-liquid impactor separator has a perforated layer of coalescence media having at least one aperture through which the gas-liquid stream flows. Improved performance is provided by increased penetration of the flow into the media patch and thereby enhancing particle capture by interception, impaction and diffusion.
U.S. Pat. No. 8,191,537 discloses a crankcase ventilation system for an internal combustion engine including a separator and an amplifier increasing at least one of flow and pressure along the flow path through the separator to provide higher separation efficiency.